When saving your work, please leave the default comment but add what you actually mapped, for example "added buildings and a residential road".

Download the relevant CanVec tile from NRCan. There is an index map (for the NTS tile system) at Toporama, under the "Grids" Theme. See the OSM Wiki for an explanation of the indexing system.

Load the tile into JOSM.

Create a new data layer, and download the data already in OSM for that tile into the data layer.

Merge the wood (natural=wood), wetlands (natural=wetland), residential areas, water features (natural=water, and waterway=), and address interpolation ways ("addr:interpolation"=) from the CanVec layer to the data layer, if the data is not already in OSM.

With imagery, ensure that the new features have some correspondence with reality.

(Optional) Join adjacent wetlands and forests.

Join connecting address interpolation ways.

Upload the data, fixing any warnings (except "Overlapping Water Areas"), and mention what CanVec tiles you used.